janus.js: createOffer update, including an external stream, fails

[mgarabedian]

While testing an update to createOffer in janus.js, I came across a bug. The following code, called a second time (update), will attempt to add the stream again in 'streamsDone' function.

instance.createOffer({
      stream: myCustomStream,
      media: {
          removeVideo: this.videoMuted,
          removeAudio: this.audioMuted,
          audioSend: this.audioMuted ? false : true,
          videoSend: this.videoMuted ? false : true,
          audioRecv: false,
          videoRecv: false,
      }
  });

I believe ths issue is here, in streamsDone. config.streamExternal is always true and always setting addTracks = true.

// We're now capturing the new stream: check if we're updating or if it's a new thing
var addTracks = false;
if(!config.myStream || !media.update || config.streamExternal) {
  config.myStream = stream;
  addTracks = true;
} else { ...

[lminiero]

Please check #2604, it's changing things there.